MOC PSSM CME Article Venous Thromboembolism Prophylaxis

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Plastic and Reconstructive Surgery September 2008, concern over bleeding complications secondary to factor V resists inactivation by activated protein C. chemoprophylaxis and drives unchecked clot formation Prothrom. bin 20210A a variant found in 1 7 to 3 percent of, INCIDENCE OF VENOUS people of European descent results in elevated. THROMBOEMBOLISM prothrombin levels and hypercoagulability Ac. Plastic surgery is not immune to the dangers of quired hypercoagulable disorders can stem from. venous thromboembolism with rates of venous pharmacologic interaction or disease sequelae. thromboembolism ranging from less than 1 percent and include antiphospholipid antibody syn. to nearly 10 percent depending on the surgical drome hyperhomocysteinemia and cancer 20 21 In. procedure 2 14 18 In a survey of members of the Amer cancer there are multiple mechanisms by which. ican Society for Aesthetic Plastic Surgery Reinisch et the prothrombotic machinery is jump started 21. al reported a 0 49 percent rate of venous thrombo Malignancies such as gastric and pancreatic types. embolism in face lift procedures 2 Chen et al found express tissue factor like material that activates. a 0 57 percent incidence of venous thromboem coagulation By means of an acute inflammatory. bolism in patients undergoing head and neck phase reaction tumor infiltrating macrophages. reconstruction 14 In a series of pedicled transverse can promote thrombus formation through inter. rectus abdominis myocutaneous flaps for breast re leukin 1 and tumor necrosis factor production. construction Erdmann et al observed a 1 3 percent Malignancies can also down regulate endothelial. rate of venous thromboembolism 15 Concerning cell anticoagulant activity and stimulate release of. large volume liposuction procedures one series re fibrinogen and factor VIII. ported a 1 7 percent incidence of venous thrombo, embolism in patients undergoing 5 liters or more of. fat aspiration 16 Grazer and Goldwyn cited a 1 9 per NATURAL HISTORY OF VENOUS. cent incidence of venous thromboembolism in a THROMBOEMBOLISM. series of abdominoplasty patients 17 Belt lipectomy The natural history of surgery associated ve. procedures are associated with the highest rate of nous thromboembolism events has been well de. venous thromboembolism approximately 9 4 per scribed by Kearon22 and is summarized below Up. cent in a recent study by Aly et al 18 to all three components of Virchow s triad may be. present at the time of surgery to promote venous, CAUSE OF VENOUS thrombosis explaining how perhaps 50 percent of. THROMBOEMBOLISM deep vein thromboses associated with surgery start. As described by the German pathologist Ru intraoperatively Most of these intraoperative. dolf Virchow venous thrombus formation is deep vein thromboses begin in the distal veins. driven by a triad of factors 1 venous stasis 2 specifically in the calf region Approximately 50. vascular injury and 3 hypercoagulability 19 At percent of deep vein thromboses formed intraop. least one part of the triad is necessary to initiate eratively may resolve spontaneously within 72. the coagulation cascade Fig 1 During surgery hours with venous thromboprophylaxis facilitat. the combination of general anesthesia supine po ing lysis of perioperative deep vein thromboses. sitioning and immobilization promotes venous and preventing formation of new thrombi Iso. stasis Decreased venous return prevents clearance lated calf deep vein thromboses rarely cause leg. of activated clotting factors leading to thrombus symptoms or clinically important pulmonary em. accumulation behind venous valve cusps Intimal bolisms Of more concern approximately 25 per. damage is also a byproduct of surgery secondary cent of untreated symptomatic calf deep vein. to venous traction during muscle and tissue re thromboses extend to the proximal veins at or. traction and the vasodilatory effect of anesthesia above the popliteal vein within 1 week of presen. At these intimal sites of microscopic injury plate tation The majority of patients with a symptom. lets collect and initiate the coagulation cascade 9 atic proximal deep vein thrombosis and without. Hypercoagulability can be secondary to inher chest symptoms have evidence of a pulmonary. ited or acquired coagulation disorders 20 21 Com embolism on lung scan The highest risk period. mon inherited prothrombotic disorders include for fatal postoperative pulmonary embolism oc. factor V Leiden prothrombin 20210A and defi curs 3 to 7 days after surgery with approximately. ciencies of protein C protein S and antithrombin 10 percent of symptomatic pulmonary embolisms. III 20 Factor V Leiden present in roughly 4 to 6 fatal within 1 hour of first symptoms Further. percent of Caucasians represents the most com more the risk of symptomatic venous thrombo. mon genetic prothrombotic defect The mutated embolism is highest within 2 weeks of surgery and. Volume 122 Number 3 Venous Thromboembolism Prophylaxis. Fig 1 Coagulation cascade,Plastic and Reconstructive Surgery September 2008.
remains elevated for approximately 2 to 3 months thromboprophylaxis is dependent on venous. After a diagnosed pulmonary embolism 50 per thromboembolism risk assignment and the 2004. cent of patients have right ventricular dysfunction American College of Chest Physicians overall rec. on echocardiography After a symptomatic deep ommendations on prophylaxis for surgical pa. vein thrombosis there is an approximately 10 per tients within each venous thromboembolism risk. cent cumulative incidence of severe postthrom category 21 24. botic syndrome after 5 years In approaching venous thromboembolism. risk assignment we advocate an individualized as, RISK ASSIGNMENT FOR VENOUS sessment of thrombotic risk as described by. THROMBOEMBOLISM Bergqvist et al Fig 2 21 This approach takes into. Given that up to two thirds of patients with a account a patient s unique set of predisposing risk. venous thromboembolism may appear clinically factors such as age history of venous thrombo. silent 23 leading to a substantial delay in diagnosis embolism and chronic illness and any exposing. and treatment and resulting in significant mor risk factors such as type and length of operation. bidity and mortality the need for thrombopro The various risk factors are differentially weighted. phylaxis is paramount Because of the elective na on the basis of historical incidence data from prior. ture of many plastic surgical procedures it is of randomized trials Tallying a patient s set of pre. paramount importance that the surgeon allow for disposing and exposing risk factors yields an over. appropriate planning and risk reduction strate all risk factor score and assignment to one of four. gies Based on the authors preference choice of venous thromboembolism risk categories low. Fig 2 Venous thromboembolism risk assessment model Reprinted from Bergqvist et. al Venous thromboembolism and cancer Curr Probl Surg 44 157 2007 with permis. sion from Elsevier, Volume 122 Number 3 Venous Thromboembolism Prophylaxis. moderate high and highest as described by the thromboprophylaxis is based on the 2004 Amer. American College of Chest Physicians 24 ican College of Chest Physicians overall guidelines. A number of risk factors with evidence based for each venous thromboembolism risk category24. weighting deserve special mention Borow and Fig 3 Thromboprophylaxis begins with proper. Goldson reported a 20 percent incidence of deep patient positioning on the operating table and. vein thrombosis for procedures lasting 1 to 2 hours early ambulation postoperatively Flexion of the. compared with a 62 5 percent rate of deep vein patient s knees to approximately 5 degrees will. thrombosis in operations taking 3 or more maximize venous return through the popliteal. hours 25 Given that the incidence of venous throm vein Proper patient positioning and early mobi. boembolism is proportional to surgical duration lization are sufficient for patients of low venous. operations are scored 1 to 5 depending on the thromboembolism risk but must be supplemented. length of surgery The above scoring system is with mechanical and or pharmacologic prophy. especially applicable in plastic surgery where pa laxis for patients with more significant venous. tients may undergo lengthy free tissue transfer thromboembolism risk. procedures Patients with a malignancy have up to, a 6 fold increase in the incidence of venous throm. boembolism as compared with those without a Mechanical. malignancy with the risk of venous thromboem The 2004 American College of Chest Physi. bolism not disappearing with cancer cure or cians overall recommendations for surgical pa. remission 21 These observations translate into a tients include the option of mechanical throm. risk score of 3 for present cancer and 2 for a boprophylaxis as stand alone therapy in both. previous malignancy which particularly relates moderate and high venous thromboembolism risk. to patients undergoing reconstructive operations groups and as combination therapy with chemo. for head and neck or breast cancer prophylaxis in highest venous thromboembolism. Women on hormonal contraception and re risk patients 24 Use of mechanical prophylaxis. placement therapy also pose a higher venous should begin before the induction of anesthesia. thromboembolism risk Overall observational data especially if general anesthesia is used and con. are consistent with a 3 to 6 fold increase in the risk tinue into the postoperative period until the pa. of venous thromboembolism with oral contracep tient is fully mobile 4 Educating nurses about the. tive pill use and a 2 to 4 fold increase in risk with importance of venous thromboembolism prophy. hormone replacement therapy 26 Oral contracep laxis is critical to ensuring compliance with me. tive pills and hormone replacement therapy both chanical methods of prevention Contraindica. contain estrogen which lowers protein S levels tions for mechanical prophylaxis include severe. and promotes thrombosis The risk of venous peripheral arterial disease congestive heart failure. thromboembolism is highest within the first and acute superficial or deep vein thrombosis. month of starting hormonal medications and di Mechanical methods of thromboprophylaxis. minishes but does not disappear after the first either passive or active have been shown to. year In this risk assessment model hormone re reduce the risk of deep vein thrombosis in a num. placement therapy or oral contraceptive pill use ber of patient groups Passive mechanical throm. earns the patient a risk score of 1 Although de boprophylaxis includes graduated compression. finitive studies on the optimal time of hormonal stockings which prevent deep vein thromboses by. medication discontinuation are lacking we sug improving valve function reducing distention of. gest discontinuation of hormonal medications at the vein wall and increasing venous flow velocity. least 2 weeks before surgery through cross sectional area reduction In some. reports use of graduated compression stockings, VENOUS THROMBOEMBOLISM reduced the rate of deep vein thrombosis by ap. PROPHYLAXIS proximately 50 to 64 percent in general surgery. Primary venous thromboprophylaxis is the patients 27 Active mechanical methods of throm. most useful and cost effective strategy for reduc boprophylaxis include intermittent pneumatic. ing the risk of venous thromboembolism in plastic compression devices and venous foot pumps. surgery patients Diagnostic tests for asymptomatic Deep vein thrombosis prevention is achieved by. deep vein thrombosis screening remain expen relieving venous stasis through increased motion. sive impractical and inaccurate and waiting for of blood and by stimulating fibrinolytic activity. symptoms to develop before taking action gambles through reduction of plasminogen activator 1 28. with the patient s long term health Choice of In a study of face lift patients intermittent pneu. Plastic and Reconstructive Surgery September 2008, Fig 3 Venous thromboembolism prophylaxis guidelines Reprinted from Geerts et al Pre.
vention of venous thromboembolism The Seventh ACCP Conference on Antithrombotic and. Thrombolytic Therapy Chest 126 3 Suppl 338s 2004 with permission from Elsevier. matic compression devices led to a significant de Chemoprophylaxis. crease in the rate of venous thromboembolism as The 2004 American College of Chest Physicians. compared with no thromboprophylaxis 59 2 per overall guidelines provide the option of chemopro. cent versus 4 1 percent respectively 2 In patients phylaxis as stand alone therapy in moderate high. with contraindications to lower extremity com and highest venous thromboembolism risk groups. pression devices mechanical prophylaxis can be or as combination therapy with mechanical prophy. applied to the arm with adequate reduction in the laxis in highest venous thromboembolism risk. incidence of venous thromboembolism as re patients 24 Chemoprophylaxis agents include low. ported by Knight and Dawson 29 The site of active dose unfractionated heparin low molecular weight. mechanical prophylaxis is not critical with studies heparin fondaparinux and vitamin K antagonists 30. demonstrating a decreased incidence of venous Contraindications to chemoprophylaxis include ac. thromboembolism with thigh high knee high or tive bleeding heparin induced thrombocytopenia. plantar compression devices 2 worsening renal insufficiency coagulopathy recent. Volume 122 Number 3 Venous Thromboembolism Prophylaxis. MOC PSSM CME Article Venous Thromboembolism Prophylaxis in Plastic Surgery Patients Mitchel Seruya M D Stephen B Baker D D S M D Washington D C Learning Objectives After studying this article the participant should be able to 1 Understand and appreciate the incidence of venous thromboembolism in plastic surgery 2 Understand and describe the cause and natural history of venous

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